How to Grow and Propagate Nasturtium (Tropaeolum majus) as a Houseplant, Plus Things to Watch Out For

Many people like to grow some “highly attractive” flowering plants at home, not only to decorate their rooms, but also to cultivate their character and add more fun to life. Nasturtium (Tropaeolum majus) is a very gorgeous flower; not only are its blooms rich and vivid in color, but its leaves are also uniquely shaped and especially beautiful, making it one of everyone's favorite flowering plants to grow at home. So how exactly should potted nasturtium be grown to do well?

Growing Methods and Precautions for Household Potted Nasturtium

Note: For potted nasturtium, first, choose a properly blended growing medium; second, strengthen fertilizer and water management during the growing period; third, make sure there is fairly ample sunlight.

1. For the growing medium, it is best to use a loamy soil blended from 4 parts leaf mold, 4 parts garden soil, 1 part compost soil, and 1 part sandy soil.

2. During the growing period, nasturtium often shows long internodes and yellow leaves, thin stems and small leaves, or lush branches and leaves but sparse flowers because of improper fertilizer and water management. During growth, generally apply 1 time per month a 20% concentration of decomposed soybean cake water; during the flowering period, stop applying nitrogen fertilizer and instead apply 0.5% superphosphate or decomposed chicken and duck manure water, applied 1 time every half month; after the flowers fade, apply 1 topdressing of 30% decomposed soybean cake water to replenish the nutrients consumed by flowering.

In summer, when the weather is hot, stop fertilizing. In late autumn, apply 1 more application of a compound overwintering fertilizer to strengthen the plant's cold resistance. Watering is a routine management task; the number of waterings and the amount of water should be determined according to the weather and the plant's growth. In spring and autumn, generally water 1 time every other day; in summer, water 1 time every day to maintain relatively high air humidity. When flower buds appear, the number of waterings should be appropriately reduced, but the amount of water each time should be increased, so that the potting soil alternates between dry and moist. After flowering, watering should be reduced.

3. Nasturtium likes sunlight by nature; in spring and autumn it should be placed in a spot with ample sunlight, while in summer it needs appropriate shading. In winter, keep the room temperature at around 15°C with ample sunlight, and it can continue to grow and develop. Nasturtium is susceptible to aphids and whiteflies, so pay attention to spraying for control.

Propagation Methods for Nasturtium

1. Sowing: Generally, the sowing period is from March to June, and the flowering period is from August to December. Sowing in late August or early September in autumn is also fine; in that case, it will bloom around New Year's Day and during the Spring Festival. The suitable germination temperature for nasturtium is 18-20 degrees; after spot sowing, cover with about 1 cm of soil, water thoroughly and keep moist, and it will germinate in 7 days. When there are 2-3 true leaves, pinch out the growing tip and pot up; appropriately arrange the leaves and branches to improve ventilation and make the flowers show.

2. Cuttings: Take cuttings from April to June, select tender stems as cuttings, remove the lower leaves, shade after insertion, and keep humid; roots can form in 2-3 weeks. As the stems and vines grow, promptly set up a support with bamboo strips and tie the branches and vines. Apply topdressing 1 time every 10-15 days, and maintain sufficient moisture and relatively high air humidity throughout the entire growing period.

Common Pest and Disease Control for Nasturtium

1. Mosaic disease

Symptoms: Affected leaves show original mosaic-type symptoms of alternating yellow-green and dark green, the leaves become smaller, and the whole plant looks somewhat stunted.

Pathogen: The pathogen of mosaic disease may be a type of cucumber mosaic virus.

Control method: Manually remove diseased leaves, and promptly burn the diseased leaves to prevent the pathogen from infecting again.

2. Ringspot disease

Symptoms: Ring-shaped mosaic or necrotic spots form on affected leaves.

Pathogen: Broad bean wilt virus, belonging to the genus Fabavirus, also known as nasturtium ringspot virus. An RNA virus; the virus particles are spherical, with a diameter of 26 nm. There is a type of aphid that is a transmission vector of ringspot disease, such as the green peach aphid and the bean aphid. However, the aphid's nature as a transmission vector is not persistent.

Control method: Control aphids in time. Commonly used insecticides include 50% malathion emulsifiable concentrate at 1000 times dilution, or 40% dimethoate emulsifiable concentrate at 1000-1500 times dilution, or compound fruit emulsifiable concentrate (40% dichlorvos, 10% omethoate) at 2000-3000 times dilution, or 20% fenpropathrin emulsifiable concentrate at 3000 times dilution, etc.

Pruning Methods for Nasturtium

After pinching: After pinching, apply fertilizer and water again; generally, in about 10 days the new branches that emerge can reach several centimeters in length. When the plant grows 15-20 cm above the pot surface, a support needs to be set up, and the vines should be evenly tied to the support, with the leaves facing one direction.

The size of the support should be such that the vines and leaves can cover the support in the later growth stage; generally it is about 20 cm above the pot surface. Tie as the stems grow, and make sure the vines are evenly distributed on the support.

After pruning the mature plant: Pruning the mature plant is done to make it branch more, so as to achieve a beautiful shape with abundant flowers and lush leaves. After pruning, pay attention to watering at the right time so the plant maintains a good growth state.

As described above, nasturtium is not only gorgeous, but also a relatively easy flowering plant to grow. Friends who like it might as well plant one or two pots on their home balcony; looking often at such gorgeous and brilliant flowers will make you feel more cheerful and joyful!